Low fat diets that contain excessive calories will cause your body to create fat. Various types of diets, regardless of macronutrient preferences, will cause the body to manufacture fat if the calorie level exceeds what the body can use.
The human body requires dietary fat. Different types of fat are required for various functions. Vitamins A, D, E and K are called fat-soluble vitamins because they require fat to be absorbed and stored. Essential fatty acids, required by the human body for good health, are released after the digesting certain fats.
Not all fats are created equally. Some are healthier than others; one should be avoided, but most should be included in almost everyone's nutritional strategies. Monounsaturated, polyunsaturated, saturated and trans fats are all similar in chemical properties but all those involved in the fitness lifestyle should learn the differences between the various types of fats.
Not All Dietary Fats Are Created Equal
Monounsaturated FatsMonounsaturated fats can help your blood cholesterol levels and reduce your chances of heart disease by reducing your low density lipoprotein (LDL) levels.  LDL is known as bad cholesterol because it can help plaque build up to clog arteries, leading to atherosclerosis and peripheral artery diseases. Monounsaturated fats are easy to find and are a good substitute for those who are looking to lower saturated fat levels without eliminating fat from their diet.
Sources of monounsaturated fats include:
- Olive oil
- Canola oil
- Peanut oil
- Majority of nuts
- Sunflower oil
Polyunsaturated FatsLike monounsaturated fats, polyunsaturated fats also improve your blood cholesterol level. They also lower your triglyceride levels and may lower your chances of developing type-2 diabetes.
Perhaps the most important characteristic of polyunsaturated fats are the inclusion of the essential fatty acids (EFA), commonly known as omega-3 and omegas-6 fatty acids. Our bodies can't synthesize these fatty acids but we require them for proper health. 
Proper brain function and cell growth require EFA's. These two EFA's are the only essential fatty acids and they are relatively easy to include in your nutritional plan.  Many metabolic processes require essential fatty acids and inadequate levels of EFA's may contribute to osteoporosis and other diseases. 
Omega-3 fatty acids have been shown to lower the chances of heart attacks by slowing plaque from accumulating in the arteries and slightly lowering blood pressure. 
Omega-6 fatty acids in both safflower and sunflower oils have shown promising results in lowering the chances of cardiovascular disease by helping to control blood sugar levels.  Docosahexaenoic acid (DHA) is an omega-3 fatty acid that is required for the body to maintain optional operation of the cerebral cortex, skin, brain, retina and other crucial aspects of the human body.
Elevated levels of DHA have been connected with lower chances of breast cancer.  Additionally, DHA is crucial for retinal stimulation and vital for the gray matter in your central nervous system. Gray matter is involved in hearing, seeing, muscle control, memory, speech and many other important functions. 
Sources of omega-3 and omega-6 fatty acids include:
- Fish, including mackerel, trout, albacore tuna and salmon.
- Olive oil
- Canola oil
- Pumpkin seeds
- Sunflower seeds
- Flax seed
- Chia seeds
- Hemp seeds
Saturated FatSaturated fats may be less healthy than mono and polyunsaturated fats but they are not a fat that must be completely avoided. The American Heart Association recommends that up to 7% of your daily calories come from saturated fats. 
Traditionally, saturated fats have been a fat associated with increased levels of bad cholesterol and heart disease. This may or may not be the case. Recent studies have shown that saturated fats may not be as harmful as previously thought, including one that found there in not conclusive evidence proving that Cardiovascular disease risks are increased by consuming dietary saturated fat. 
There are additional studies that confirm there is not conclusive evidence of cardiovascular disease but the most nutritionists will recommend that you limit your saturated fat intake and receive the majority of your fat calories from the unsaturated fats. [11,12] Substituting unsaturated fats for saturated fats when possible is a great way to reach your daily fat goals but don't eliminate saturated fats completely.
Saturated fats also influence Sources of saturated fats Include:
- Poultry with skin
- Beef fat
- Most animal fat
- Trans fats
oronary heart disease (CHD) is the main health risk connected with trans fat.  Trans fat has consistently been shown to be associated with increased risk of the world's biggest cause of death, (CHD).  Bad cholesterol (LDL) levels are increased and good cholesterol (HDL) levels are reduced with trans fat ingestion. 
There is absolutely no reason to add or keep trans fat in your diet. It is estimated that close to 100,000 deaths a year in the United States may be attributed to trans fat ingestion.  Check the labels on your food to ensure that you are not eating trans fat in any amounts. Trans fat has already been eliminated from most products but be aware that trans fats are often used in the shortenings that restaurant use to deep fry food. 
Dietary fat is a necessary and important macronutrient that needs to be a part of everyone's nutritional strategy. Learning the differences between various fats and how you can benefit from them will provide a more complete understanding on how to properly fuel yourself.
Include fat in your diet; utilize unsaturated fats but don't try to eliminate saturated fat completely. Most healthy sources of unsaturated fats contain some saturated fat. Personally, my favorite reason for including fat in my diet is a time-tested fact that can be summed up by one of my favorite quotes, " things that have fat in them taste way better than things that don't. "